Specifically, though not exclusively, the invention is usefully applied in the field of dental aspiration plants.
As is well known, dental aspiration plants enable fluids to be removed from the mouth of a patient during a dental operation. These fluids comprise a gaseous part, generally air, a liquid part, generally water, blood and other liquids which are used in the dental plant) and a solid part which is made up of particles, generally obturation material and other debris. The flow of the aspirated fluids, which contain various polluting substances, is usually discontinuous and can be quite substantial, such as, for example, when the plant is being washed and flushed out.
The separated liquids, before being discharged into the municipal sewers, have to be treated in order to remove the polluting substances. Whatever the nature of this treatment, a counter-pressure is generated in outlet which hinders the exit of the liquids from the plant. Other and many-varied factors (both constant and accidental) can cause a similar counterpressure.
In plants equipped with an air-liquid separator centrifuge, i.e. a separator in which the fluid to be separated enters and subsequently exits through different outlets, the air (or other gases) being aspirated by the separator, for example by a suction pump, and the liquid being sent on to subsequent treatments before being discharged into the sewers, it can happen that an excessive incoming fluid flow leads to difficulty in liquid discharge, possibly giving rise to a flooding in the separator, with liquid being sucked into the air outlet. This drawback is to be avoided, as it can lead to serious damage of the air suction pump.
As it is not possible to discharge any excess liquid directly into the sewers, various solutions have been offered to obviate this drawback.
A first of these solutions consists in halting plant operation (in practice this means shutting down the suction pump) when the liquid level or the pressure of liquid in the pipe goes over a certain level. This is a rather drastic solution which is not popular with users.
Another solution consists in providing a buffer tank which, when the level of the liquid or the pressure of the liquid in the pipe goes over a certain level, receives the excess liquid which is then sent on to subsequent treatments before being discharged into the sewers. This solution, though quite functional in other areas, leads to a complication in the construction of the plant as well as to an increase in its size.
The main aim of the present invention is to obviate the above-mentioned drawbacks in the prior art, by providing a device which simply and economically prevents separator flooding in any operating circumstances without shutting down aspiration plant operation.
An advantage of the device is that it can be easily applied on known-type plants.
A further advantage is that it provides a device which, in case of necessity, activates and deactivates automatically with no need for manual intervention on the part of the operator, nor any need for an external energy supply, such as electrical or pneumatic energy, or any other type.
These aims and advantages and more besides are all achieved by the invention as it is characterised in the claims that follow.